This request for support is for the continuation of the research in progress at the Oregon Regional Primate Research Center and for the inclusion of two new projects (listed under 9 and 10). Studies will continue on: 1) a number of aspects of the structure of human skin and that of other mammals under normal, aging and pathological conditions; 2) the in vitro growth of pigment cells from rhesus monkey eyes; 3) turmorigenicity and melanogenesis of somatic cell hybrids; 4) the relation of cyclic AMP and melanoma cells; 5) the destruction of melanoma cells by macrophages; 6) surface antigenicity of melanoma hybrids; 7) chemical and ultrastructural characterization of melanosomes in albinism; 8) the characterization of autonomic nerves in the skin of human and nonhuman primates; 9) pathogenesis of human and nonhuman primate xanthomas as compared with that of atheromata; and 10) the enzymes which reduce or oxidize superoxide in human skin. BIBLIOGRAPHIC REFERENCES: Montagna, W. 1977. Morphology of cutaneous receptors. In: Advances in Biology of Skin. Vol. XVIII. Cutaneous Innervation and Modalities of Cutaneous Sensibility. (W. Montagna, and J.M. Brookhart, eds.). J. Invest. Dermatol, in press. Montagna, W., and Brookhart, J.M., eds. 1977. Advances in Biology of Skin. Vol. XVIII. Cutaneous Innervation and Modalities of Cutaneous Sensibility. J. Invest. Dermatol., in press.